1. Field of the Invention
The present invention relates to a diecasting machine utilizing a hybrid hydraulic circuit.
2. Description of the Related Art
A diecasting machine is an apparatus in which a piston of an injection cylinder is actuated by hydraulic pressure to inject and load molten metal fed to a molten metal loading sleeve into a clamped mold at high speed and, after pressure maintaining/cooling is performed at high pressure, the mold is opened to remove the diecast product. For the operation cycle to be shortened, the opening and closing of the mold need be performed at high speed. On the other hand, in mold clamping which applies high pressure to the mold, a movable mold member need be moved toward a stationary mold member at low speed for avoiding damage to the mold, and when the mold members substantially fit each other, high pressure is applied to clamp the mold.
For this reason, a prior-art diecasting machine B employs a toggle mechanism G as a mold clamping device, as shown in FIG. 3. However, such a toggle mechanism G is mechanically complicated and often suffers from mechanical troubles. Further, since the prior-art diecasting machine has a high parts count, the machine has a disadvantage in terms of cost. Although a clamping device of the direct-acting type is also available, an expensive booster cylinder need be used to realize the above-described operation, which also results in an increased cost, as known from U.S. Pat. No. 4,861,259.